Joint Structure + function Flashcards
Arthrology is the study of joints. Joints (when 2 or more bones that meet + are connected) can be classified as cavitated joints or solid joints. Explain which types of joints fit these categories
cavitated joints= synovial
solid joints= cartilaginous + fibrous
Describe the structure + components of a synovial joint
A synovial joint consists of two bony surfaces that are encompassed by a fibrous articular capsule (outer) with a synovial membrane lining (inner). The joint contains a joint cavity filled w synovial fluid, which allows the bony surfaces to articulate with each other. It also has articular cartillage on either side of bone. The extracellular matrix consists of water and proteoglycans (glycosaminoglycan and hyaluronic acid).
name the 6 different types of synovial joints + relate to the amount of movement these permit + give examples
- planar joint = articular surfaces are flat; side to side/back + forth gliding movements e.g. intercarpals, intertarsals, facet joints of vertebral column, acromioclavicular
- hinge joint= convex surface of 1 bone fits into concave surface of another bone; flexion/extension in a single plane e.g. elbow, knee
-
pivot joint= round or pointed surface of 1 bone fits a ring formed by another bone + a ligament; rotational movements e.g. atlas rotating about the axis, radius in annular ligament of ulna
ellipsoid joint** (aka condylar joint)= oval shaped condyle of 1 bone fits into elliptical cavity of another bone; flexion/extension, abduction/adduction + circumduction e.g. joint between carpals + radius, temporal mandibular joint
**saddle joint= one bone is saddle shaped the other is a rider; flexion/extension, abduction/adduction + circumduction e.g. carpometacarpal joint of thumb
*ball & socket joint= ball-shaped surface of one bone fits into cup-like depression of other; flexion/extension, abduction/adduction, rotation + circumduction e.g. shoulder + hip joints
what kind of joint is between the interosseous margins of radius and ulna
its the * interosseous membrane* which is a fibrous joint of the forearm (rarely called middle or intermediate radioulnar joint) is a fibrous sheet that connects the interosseous margins of the radius and the ulna. It is the main part of the radio-ulnar syndesmosis, a fibrous joint between the two bones.
what kind of joint is the epiphyseal growth plate
A synchondrosis (aka joined by cartilage), or** cartilaginous joint**, only connected by hyaline cartilage and can be temporary or permanent. A temporary cartilaginous joint is an epiphyseal growth plate. It functions to permit bone lengthening during development
in a new born, the sutures of the skull are much wider; why is this?
the skull is moldable, cuz the skull bones are able to override eachother when being birthed. The sutures are connected by fibrous tissue just more of it than adult, these wide sutures allow skull to grow during early childhood.
what is a syndesmosis
A syndesmosis is defined as a fibrous joint in which two adjacent bones are linked by a strong membrane or ligaments aka its a sheet of fibrous tissue between bones
what is a gomphosis?
A gomphosis is a fibrous joint that anchors a tooth to its socket via the periodontal ligament (a fibrous tissue). Gomphoses line the upper and lower jaw in each tooth socket and are also known as peg and socket joints. These joints have a very limited range of mobility so the teeth are held firmly in place.
what kind of joint is the pubic symphysis and what kind of cartillage connects it
pubic symphysis is a cartilaginous joint connected by fibrocartillage (n.b. just like the intervertebral discs)
what kind of cartillage are epiphyseal growth plates and costochondral joints (n.b. CONNECT RIBS TO STERNUM) made of?
hyaline cartillage
the articular capsule of a synovial joint has 2 layers, what are they?
the articular capsule encloses the synovial cavity uniting articulating bones; it has 2 layers:
* outer fibrous capsule (may contain ligaments)
* inner synovial membrane (secretes lubricating + joint nourishing synovial fluid)
osteoarthritis is the degenration of what type of cartillage?
ostearthritis is the degeneration of articular cartilage
what is articular cartilage made of?
articular cartilage is made of hyaline cartilage:
- smooth, slippery + v low coefficient of friction
- elastic, resilient; shock absorber to protect underlying bone
- deeper layer merges via calcified layer w the subchondral bone
- properties depend on composition of ECM (extracellular matrix)
-80% water
-collagen type II
-proteoglycans
what are the 3 primary functions of synovial fluid
- lubrication
- nutrient distribution
- shock absorption
what are bursae
a bursa is a small sac lined by synovial membrane, + filled w synovial fluid. Bursae are located at key points of friction in a joint.
- bursae allow for greater freedom of movement whilst protecting the articular surfaces from friction-induced degeneration
- bursae can become inflamed following infection or irritation by over use of the joint (bursitis)
- bursae (sometimes extensions of the joint capsule)
